Abstract: The present invention is a composite material, a process and a product formed by the process. The composite is formed by a process that includes forming a fibrous structure comprising fibers into a preform, coating the fibers of the fibrous structure preform with elemental carbon to impregnate that preform, infiltrating the preform with boron carbide to form an impregnated green body. The impregnated green body is infiltrated with liquid naphthalene or other carbon precursor, which is thereafter pyrolyzed to form a carbon char. Then, the char infiltrated green body is infiltrated with molten silicon to form a continuous matrix throughout the composite. The silicon in the continuous matrix is reacted with the carbon char to form silicon carbide.

Abstract: The present invention is a composite material and process to produce same. That material comprises a fibrous structure which is initially predominantly coated with elemental carbon; that fibrous structure is then subsequently predominantly coated with at least one ceramic material, e.g., boron carbide, which is non-reactive with silicon. The composite material also comprises a silicon matrix which is continuous and predominantly surrounds the fibrous structure, which has been initially predominantly coated with elemental carbon and subsequently predominantly coated with at least one ceramic material. The matrix which has a fine grain crystalline structure of predominantly 20 microns or less in size. The at least one ceramic material is discontinuous within that matrix. The fibrous material pulls out of the elemental carbon, which initially predominantly coats that fibrous structure, when the composite is subjected to fracture.

Abstract: The present invention is a composite material, a process and a product formed by the process. The composite is formed by a process that includes forming a fibrous structure comprising fibers into a preform, coating the fibers of the fibrous structure preform with elemental carbon to impregnate that preform, infiltrating the preform with boron carbide to form an impregnated green body. The impregnated green body is infiltrated with liquid naphthalene or other carbon precursor, which is thereafter pyrolyzed to form a carbon char. Then, the char infiltrated green body is infiltrated with molten silicon to form a continuous matrix throughout the composite. The silicon in the continuous matrix is reacted with the carbon char to form silicon carbide.

Abstract: The present invention is a composite material and process to produce same. That material comprises a fibrous structure which is initially predominantly coated with elemental carbon; that fibrous structure is then subsequently predominantly coated with at least one ceramic material, e.g., boron carbide, which is non-reactive with silicon. The composite material also comprises a silicon matrix which is continuous and predominantly surrounds the fibrous structure, which has been initially predominantly coated with elemental carbon and subsequently predominantly coated with at least one ceramic material. The matrix which has a fine grain crystalline structure of predominantly 20 microns or less in size. The at least one ceramic material is discontinuous within that matrix. The fibrous material pulls out of the elemental carbon, which initially predominantly coats that fibrous structure, when the composite is subjected to fracture.

Abstract: This invention relates to a process comprising the steps of: a) providing a fiber preform comprising a non-oxide ceramic fiber with at least one coating, the coating comprising a coating element selected from the group consisting of carbon, nitrogen, aluminum and titanium, and the fiber having a degradation temperature of between 1400° C. and 1450° C., b) impregnating the preform with a slurry comprising silicon carbide particles and between 0.1 wt % and 3 wt % added carbon c) providing a cover mix comprising: i) an alloy comprising a metallic infiltrant and the coating element, and ii) a resin, d) placing the cover mix on at least a portion of the surface of the porous silicon carbide body, e) heating the cover mix to a temperature between 1410° C. and 1450° C. to melt the alloy, and f) infiltrating the fiber preform with the melted alloy for a time period of between 15 minutes and 240 minutes, to produce a ceramic fiber reinforced ceramic composite.

Abstract: This invention is directed to substantially strain-free, shaped, sintered ceramic fabric preform segments, to the production of the sintered preform segments from novel fixtured, shaped, green ceramic fabric preforms, and to sintered ceramic fiber-reinforced composite articles prepared from the sintered preforms and characterized in that the reinforcement phase is substantially free of mechanical strain, and the fiber in the fabric can exhibit a very small bending radius.